Melting-furnace



T. F. BAILY AND F. T. COPE.

MELTING FURNACE.

APPLICATION FILED FEB. 16, 1920.

1,373,787. Patented Apr. '5, 1921.

zrnannnrrs r. BAILY AND FRANK r. corn, or ALLIANCE, onro, Assralqons ToTHE minerals FURNACE oomrm, or ALLIANCE, care, A eonroaarron (mmMELTING-EUBNACE.

wearer.

Specification of Letters Patent.

Patented Apr. a, 1921.

Application filed February 16, 1920. Serial No. 359,090.

\ of which the following is a specification.

Our invention relates to melting furnaces and more particularly to afurnace especially adapted for melting brass and provided with meansforpreventing the usual loss of a considerable percentage of the zinc fromthe brass during the melting process.

It is well known to those versed in the metallurgy of non-ferrous metalsthat inmelting brass in the usual form of melting furnace a considerableamount of the zinc from the brass is lost in the form of zinc vaporwhichmay be deposited around the furnace in the form of a' fine powder. I

This loss of zinc from the brass is probably .due to the greatdifference between the melting points of zinc and brass.v As is wellknown to those skilledin the art, brass is an alloy of copper and zincin which the proportions of. the two metals vary for different uses. Themajority of these alloys contain a very large percentage of copper,

the melting point of which is 1929. As the melting point of zinc is only779 while the melting point of brass is 1692, a considerable amount ofzinc in the alloy is vaporized during the melting of the brass.

In the ordinary melting furnace such as is in general use for meltingbrass a considerable per cent. of this zinc vapor is lost escaping fromthe furnace and being deposited around the furnace in the form of a finepowder. This loss of zinc from the brass represents not only a loss of acertain per cent. of the metal but also changes the ,proportions'of thealloy since owin to the high temperature of vaporization 0 copper thereis no loss of copper fromthe alloy during the melting process Theobjects of the invention are to provide a furnace especially adapted formelting brass in which means are provided for preventing the loss ofzinc from the brass in the form of zinc vapor, during the process ofmelting; and to generally improve and simplify melting furnaces of thischaracter. I

These objects are attained by providing one or more condensers incommunication wlth the heating chamber of the usual melting furnace, thezlnc vapor from the heating chamber passing into these condensers whereit is condensed into metallic zinc. When a condenser has become partlyfilled with metallic zinc it is removed from the furnace and the zincemptied therefrom, the zmc which is thus received into the condensersrepresenting the usual loss of zinc from the brass which in practicevaries from four to 1n some cases as high as twenty per cent. of zinc inthe alloy.

pended claims, it being understood that va- I rious changes in the form,proportions, size and minor details ofconstruction may be made wlthinthe scope of the appended clalms, without departing from the spirit orsacrificing any of the advantages of the invention.

The invention thus set forth in general terms is illustrated in theaccompanying drawings forming part hereof, in which- Figure l is avertical sectional view through a brass melting furnace showing acondenser in place upon the furnace.

Fig. 2 is an enlarged sectional. view through a tyne of condenser whichis well adapted for use with the furnace.

Fig. 3 is a fragmentary-sectional view through a portion of a furnaceshowing a modified form of condenser.

Similar numerals of reference indicate corresponding parts throughoutthe several figures of the drawings.

Although our invention may be applied to, any form of melting furnace wehave illustrated it in the accompanying drawings in connection with" anelectrically heated brass melting furnace of the type upon which weobtained United States Letters Patent No. 1,272,286, July 8, 1918.

In this form of furnace the numeral 1' indicates a metal plate uponwhich the .base 2 of the furnace is supported, this base being composedof suitable insulating material such as bricks formed of kieselguhr, ametal plate 3 being preferably located upon work 4 preferably formed offire brick and provided with the concave hearth 5 which is lined withsuitable brick, heat resisting material and provided at one side with areduced neck 6 having a pouring spout 7. A circular wall 8 formed offire brick or other suitable material is supported upon the brick work 4and a roof 9 preferably tend through concaved as shown is provided oversaid circular wall, thus forming a heating chamber between the roof,hearth and circular walls.

Mounted within the heating chamber intermediate the hearth and roofthereof and spaced from the circular side-wall is a resistance trough 10preferably circular as shown. This trough is provided with a resistancebody consisting of a carbonaceous material in granular form, such ascrushed coke, graphite, carbon or the like, said resistance materialbeing designated by the numeral 11. The trough is preferably formed ofrefractory material or the like and comprises the bottom wall 12 and thecircular upright Walls 13, and is supported upon the radial supportingwalls 14, composed of fire brick or other heat resisting material.

Embedded in the resistance material pref erably at diametricallyopposite sides of the trough are suitable electrodes 28 which exthefurnace walls in the usual manner. these electrodes are arranged in anelectric circuit, such construction being well known in this art. Whencurrent is supplied to the electrodes it will be conducted from oneelectrode to the other through the resistance material, thus raising theresistance material to an intense heat.

A metal casing 16 is preferably provided around the furnace and it willof course be understood that furnaces of this type can be mounted sothat they may be tilted to pour the melted metal therefrom and for thispurpose any usual construction may be provided for rocking or tiltingthe furnace to pour the melted brass therefrom through the pouring spout7 but this feature of the furnace construction forms no part of thepresent construction and is therefore not illustrated, since it is wellknown and in general use.

The heat rays which radiate downward from the resistance trough willstrike directly upon the hearth containing the metal to be melted whilethose rays which radiate upward from the trough will strike the archedroof, the greater majority of said rays being. reflected through thecentral opening in the trough upon the metal on the hearth- In meltingbrass in any melting furnace such as in general use, the low meltingpoint of zinc causes a certain amount of the zinc t is, of course,understood that clined neck 25 back in the brass to vaporize duringthemelting of the brass, this zinc vapor escaping from the furnace.

In order to overcome this loss we provide one or more suitable apertures17 in the upper portion of the heating chamber, a condenser 18, providedwith the reduced neck 19 being-fitted into each aperture. Each of thesecondensers is provided with the downwardly inclined condensing chamber20, a small aperture 21 being formed in the outer end of the condenserto cause a slight draft from the heating chamber through the condenserdrawing the zinc vapor which is given ofi by the melting brass into] thecondenser, the vapor contacting with the cooler walls of the condensingchamber and condensing, being deposited in the bottom of the condensingchamber in the form of metallic zinc.

Any suitable support for the condenser, such as the bracket 22 may beprovided upon the furnace wall in order that the condensersmay be heldin placeupon the furnace and easily removed therefrom when it is desiredto remove the condensed zinctherefrom. By the use of this condenser, thezinc which would ordinarily escape from the ordinary form of meltingfurnace in the form of zinc vapor is thus collected and condensed withinthe condenser, thus producing a considerable saving of zinc.

In the modification shown in Fig. 3 the condenser 18 is provided with areduced neck 19 at its upper end which fits into a suitable aperture inthe upper portion of the heating chamber, a downwardly and inwardlyinclined neck 25 being provided at the lower end of the condenser, thisneck passing through a suitable aperture 26 in the heating chamber justabove the hearth 5 of the furnace. With this construction the zinc as itis condensed within the condenser 18* will be carried through the in-=to the hearth of the furnace.

We claim:

1. A melting furnace and a condenser communicating with the heatingchamber thereof.

2. A melting furnace provided with an aperture in the heating chamberthereof and a condenser located in said aperture and communicating withthe heatin chamber.

3. A melting furnace and a condenser communicating with the heatingchamber thereof and extending beyond the exterior of the furnace.

4. A melting furnace and a condenser communicating with theheating'chambcr thereof, the condenser provided w1th a large condensingchamber having a reduced aperture at its outer extremity.

6. A brass melting furnace having a zinc vapor condenser communicatingwith the heating chamber of the furnace.

7. A brass melting furnace provided with an aperture communicating withthe heating chamber thereof and a zinc vapor condenser having a reducedneck located in said aperture and communicating with the heatingchamber.

8. A brass melting furnace and a zinc vapor condenser communicating withthe heating chamber of the furnace and extending beyond the exterior ofthe furnace.

9. A brass melting furnace and a zinc vapor condenser provided with areduced neck communicating with the heating chamber of the furnace andhaving an enlarged condensing chamber located beyond the exterior of thefurnace.

10. A brass melting vapor condenser having a reduced neck comfurnace anda zinc municating with the heating chamber of the furnace and having anenlarged downwardly inclined condensing chamber located beyond theexterior of the furnace.

11. A brass melting furnace having an aperture communicating with theheating chamber thereof and a zinc vapor condenser provided with areduced neck located in said aperture and with an enlarged condensingchamber extending beyond the exterior of the furnace and provided with areduced aperture at its outer extremity.

12. A brass melting furnace and a condenser communicating with the upperportion of the heating chamber thereof, the condenser provided with aninclined neck communicating with the heating chamber near'the hearth ofthe furnace.

In testimony that we claim the above, we have hereunto subscribed ournames.

THADDEUS F. BAILY. FRANK T. COPE.

